Flow restriction is used to tune a flow of fluid conveyed in systems where full flow capacity is not desired to balance conveyance systems. Examples of where such flow restriction is desirable includes fuel lines for aircraft or land or sea vehicles. In designing a fluid flow system, temporary methods of creating flow restriction may be used to tune the system to determine a proper restriction orifice size. Once the proper restriction orifice size is determined, a flange containing a permanent flow restriction orifice is designed and used where the flow restriction is required in the system. In some known instances, the temporary components are not qualified for permanent use. For example, in aircraft fuel lines, the temporary components may not be flight qualified.
FIGS. 1 and 2 illustrate a cross-section and a cut-away perspective view, respectively, of a prior art tube assembly 100. The assembly 100 includes a first tube T1 having a first flange F1 adjacent a second tube T2 having a second flange F2. The flanges are surrounded by a sleeve S, and o-rings O or other seals are placed between the first and second flanges F1, F2 and the sleeve S to prevent fluid from leaking, and to lock the joint together. A coupler assembly C captures the sleeve and secures the first and second flanges F1, F2 together. In one embodiment, the coupler assembly C is a clamshell design, having a first and second semi-circular component hingedly connected and configured to be locked in a closed position.
In the illustrated prior art embodiment, the second flange F2 is configured to receive a removable orifice plate 110 having an orifice with a diameter smaller than the inner diameter of the first and second tubes T1, T2, thereby restricting flow of fluid. Although the orifice plate 110 is shown as having a single orifice that is substantially circular, it should be understood that a plurality of orifices of different shapes may be employed.
The second flange F2 has a groove and shoulder on the inner diameter to receive the removable orifice plate 110. The tube assembly 100 may be disassembled to allow an operator to remove the orifice plate 110 and replace it with another removable orifice plate having an orifice of a different size. By removing and replacing orifice plates, an operator may test different sized orifices to arrive at a desirable fluid flow, thereby tuning the system.
In the illustrated embodiment, the removable orifice plate 110 contains accommodations for hardware that secures it to the second flange F2. A seal 120 is disposed between the second flange F2 and the removable orifice plate 110 (illustrated here as an o-ring) to prevent flow around the removable orifice plate 110. Additionally, a retaining wire 130 is employed to hold the removable orifice plate 110 in place.
After an operator determines a desirable orifice size, the operator may remove the second flange F2 and the removable orifice plate 110 and replace it with a unitary flange and orifice plate. FIG. 3 is a cross-section of an exemplary final tube assembly 200 having a restrictive flange 210. In one embodiment, the restrictive flange 210 is custom-made. When used in an aircraft application, the restrictive flange may be a flight-qualified component.